Hardening of topology plugin to prevent erronous deletion of a replica agreement
    
    When a segment is deleted, the underlying replica agreement is also deleted.
    An exception to this is if the status of the deleted segment is "obsolete" (i.e. merged segments)
    The status should contain only one value, but to be protected against potential
    bugs (like https://pagure.io/389-ds-base/issue/49619) this fix checks if
    "obsolete" is in the status values.
    
    https://pagure.io/freeipa/issue/7461
    
    Reviewed-By: Christian Heimes <cheimes@redhat.com>